How do I mend my fridge/freezer?

My Neff F/F (K5920L0GB) has completely iced up at the back of the fridge side and inside the drawers. I'm in the process of defrosting it but there's also ice in the drainage hole at the back. Any advice please? I've turned it off inside the fridge door but don't want the freezer to defrost so need a speedy solution.
Hoping you can help.

Irene, March 2022


done
Defrost it properly

Rjrh, April 2022
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